This application relates to communication networks. In particular, it relates to a technique for automated communication setup between neighboring nodes in a ring or mesh communication network.
In a ring configured communication network, a given node has an xe2x80x98Eastxe2x80x99 and a xe2x80x98Westxe2x80x99 neighbor node. For an application to communicate with a neighbor node, it needs to know the neighbor""s physical address for delivery of information over the physical medium of the network. This is the address resolution that is required.
When an ethernet is used in a ring topology, the destination MAC address (ethernet address) is necessary for sending a data frame to the neighbor node. Normally, for IP (Internet Protocol) packets, standard ARP (Address Resolution Protocol) can be used to bind the IP address to a MAC address. However, this would require extension for non-IP traffic. Additionally, the fact that the ethernet is connected in a ring topology for an optical ring poses problems for sending broadcast queries (which is the basis of ARP). If broadcast frames are sent around a ring, for example, the frames will circulate forever, creating a xe2x80x9cbroadcast storm.xe2x80x9d
Thus there is a need in the art for a method and a system to transmit the address of a neighbor node of a communication network without broadcasting over the network. Further, there is a need to transmit the address of such a neighbor node automatically and dynamically, such that the network updates itself without a requirement for user knowledge of any of the physical address properties of the neighbor node, thereby reducing the complexity of information that a network administrator is required to manage.
It is a primary object of this invention to provide a method and a system to transmit the physical address information of a neighbor node of a communication network without broadcasting over the network. Further, it is an object of this invention to transmit the address of such a neighbor node automatically and dynamically, such that the network updates itself. Additionally, it is an object of this invention to employ such transmitted physical address information to control network communication between neighbor nodes. Moreover, it is an object of this invention to perform such transmitting and control functions without a requirement for user knowledge of any of the physical address properties of the neighbor node, thereby reducing the complexity of information that a network administrator is required to manage.
In accordance with embodiments of the present invention, a network configuration and method provide automated communication setup between neighbor nodes in a communication network, without broadcasting this setup information over the network. Network nodes are connected to network devices, for example microcontrollers.
A signaling bandwidth separated from the data communication channel bandwidth solves the problem of address resolution to a MAC address automatically and dynamically by multiplexing over a common transmission medium. The transmission medium can be an electrical conductor or an optical fiber. The user is not required to provide any of the physical address properties of the neighbor nodes. This reduces the complexity of the information that a network administrator is required to manage.
Furthermore, the network and method according to the invention do not use a broadcast mechanism within the data channel to resolve the address of the neighbor node. Instead, they employ a link-terminated mechanism outside of the data communication channel bandwidth to perform dynamic neighbor discovery. This processing is distributed, and the resulting information feeds into a complete address resolution table, which is employed for controlling network communication, for example sharing an application, between neighbor nodes over the main data communication channel bandwidth. Once resolved, for example in an optical ring the physical address information is carried over the OSC (Optical Supervisory Channel). This technique can also scale to systems beyond a ring network configuration to bus and mesh network topologies. Appropriate communication network protocols can include Ethernet carrying IP or proprietary format traffic.
Typically, transmission and reception between neighbor nodes over the signaling bandwidth is performed using transmit and receive cards installed in the network devices connected to the respective nodes. Transmit/receive functions are sometimes combined into a xe2x80x9csignaling card.xe2x80x9d Received physical address information is provided by the signaling card to a network control device or processor, which constructs the address resolution table and controls network communication between neighbor nodes in the data communication channel bandwidth.
Some embodiments of the invention rely on substantially continuous transmission and/or reception over the signaling bandwidth to send address information between neighbor nodes. This is useful not only to determine the neighbor node""s active address upon first starting up, but also while the network is running, to detect if a signaling element has been swapped out or has changed activity. The address resolution is automatically updated to reflect a new configuration.
In some implementations according to the invention, there can be a multiplicity of neighboring network nodes, any of which can transmit physical address information to any neighbor node over the signaling bandwidth. The physical address information is used at any receiving neighbor node or nodes to obtain a network configuration.